# The Air Quality Limit Values Regulations 2001, Paragraph 4


Nature and assessment of pollution
concentrations observed over previous years (before the implementation of the improvement measures)
concentrations measured since the beginning of the project
techniques used for the assessment.

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Source: https://www.legislation.gov.uk/uksi/2001/2315/schedule/7/paragraph/4 (the official version)
Page: https://openlegislation.uk/air-quality-limit-values-regulations-2001/schedule-7/paragraph-4
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.